Electrical relay



311, 1935. F: J. CHAMPLIN ELECTRICAL RELAY Filed July 17, 1951 Inventor:-Fvanklin J. Champlin,

His Attorney.

Patented Dec. 31, 1935 UNITE STATS ELECTFJICAL RELAY Franklin J.Champlin, Dalton, Mass, assignor to General Electric Company, acorporation of New York Application July 17, 1931, Serial No. 551,536

1 Claim.

My invention relates to electrical relays and more particularly toimprovements in electromagnetically controlled relays of thecontact-making voltmeter type.

Heretofore, most contact making voltmeter type relays have included apivotally mounted contact arm. one end of which is connected to anoperating solenoid and the other end of which is connected to aresilient balancing element which is usualy referred to as compensatingspring. In practice these elements are usually so arranged that the pullof the spring partially balances the weight of the solenoid core. Thatis to say, the spring balances the otherwise unbalanced weight of thecore which is not supported by the pull of the magnet. Among the reasonsfor making it desirable to have a compensating spring, rather thanmaking the magnet so strong that it normally supports the entire weightof the core, is that by balancing a part of the core weight the magnetwill have less unbalanced weight to move and consequently it will bemore sensitive to variations in voltage. Another reason for the springis that it permits of a smaller magnet coil, that is to say, a magnetcoil having a lower ratio of reactance to resistance with the resultthat the energization of the magnet is more independent of changes infrequency of an alternating current energizing circuit. This is, ofcourse, desirable in a. voltage regulating system, where it is notdesired to make the arrangement responsive to frequency changes. Whensuch an arrangement is energized from an alternating current source, orfrom a source of pulsating direct current, I have found that thevibrations of the core of the solenoid which are produced by suchenergization of its magnet cause a vibratory action of the metercontacts with the result that they become pitted and burned and theirlife is materially shortened.

It is, of course, possible to damp out these vibrations by making theparts very heavy, or by providing an oil dashpot, or the equivalent, butall of these arrangements result in a sluggish action of the meter,which when the meter is used for controlling a voltage regulator, is notdesirable.

In accordance with the illustrated embodiment of my invention, I providean operating magnet assembly, which is itself balanced by suitablebalancing means, connected to a circuit controlling contact arm througha resilient connection whereby any frequency vibrations in the magnetassembly will be absorbed by this connection and not transmitted to thecontact arm. This contact arm should preferably be balanced although Ihave found that the slight unbalance of individual arms which is due tomanufacturing variations has no appreciable harmful efiect on theoperation.

(Cl. 20i)91) An object of my invention is to provide a new and improvedelectromagnetically operated relay. Another object of my invention is toprovide a substantially vibrationless contact arm alternating currentoperated contact-making voltmeter.

My invention will be better understood from the following descriptiontaken in connection with the accompanying drawing, and its scope will bepointed out in the appended claim.

In the drawing Fig. l is a diagrammatic illustration of a specificembodiment of my invention, while Fig. 2 is an illustration of amodification of the arrangement shown in Fig. 1.

In Fig. l or" the accompanying drawing, I have illustrateddiagrammatically an embodiment of invention which is connected to beresponsive to the voltage of and which controls the operation of aninduction feeder voltage regulator 2, connected to this ciranalternating current circuit 1 cuit, through control of the direction ofoperation of a servo operating motor 3, in the usual manner. Theoperating assembly of the relay comprises an electro-responsive device,such as a solenoid magnet 4, which is connected across circuit 5,preferably through a potential transformer 5, a core 6 for the magnet,and a compensating, or balancing, means which is preferably in the formof a resilient spring 7. Adjusting means 8 provided for varying thetension of the balancing means i. This arrangement is preferably soadjusted that with normal voltage on circuit i, spring l supports a partof the weight of core 6 and magnet lsupports the rest. If new thevoltage of circuit l increases, core 8 will move upwardly, while if thevoltage of circuit I .decreases core 6 will move downwardly. However, itwill be obvious to those skilled in the art, as the description of myinvention proceeds, that this assembly might also be so adjusted thatcoil 4 normally pulls down instead of up, without departing from myinvention in its broader aspects. The circuit controlling assembly of myrelay may comprise any kind of a movable circuit controlling arrangementand in the illustrated embodiment consists of a pivotally mountedcontact L carrying beam 9, carrying contacts for cooperating with raiseand lower contacts and II, respectively. This beam 9 is also arranged tocooperate with the usual holding coils l2 and 13.

Any suitable source of current supply for energizing the holding coilsand motor 3 may be provided, and as shown, this means consists of abattery Id.

The control circuits are so arranged that when raise contacts iii areclosed motor 3 is operated in a direction to cause regulator 2 to incrase the Voltage of circuit l and at the same time holding coil l2, whichis connected in parallel with the motor, is energized. Similarly, whenlower contacts I I are closed motor 3 is operated in a.

reverse direction to cause regulator 2 to lower the voltage of circuitI, at the same time holding coil I3 is energized.

Regulator 2 is a device which is well understood by those skilled in theart, and consists primarily of a transformer for producing. variableamounts of voltage boost or buck, in the circuit to be regulated,through variations in the inductive relation of its windings bymechanical displacement of their axes.

In order to facilitate the balancing of beam 9 I preferably a providesuitable balance means, such as anarm l5 with an adjustable weight inthe form of a nut 16. By turning this nut it will be moved along the armso as to attain a balance of the beam. This, however, is a refinementwhich is not necessary so long as the contact beam is substantiallybalanced and is not associated with any biasing means tending topositively unbalance it.

The operating connection between core 5 and beam 9 consists of aresilient element which need not be made of any particular material norneed have any particular shape. In the illustrated embodiment itconsists of a flat metallic spring ll. In order to keep the advantagesof a compact structure while at the same time having a sufficientlyflexible connection between the core and the beam, I have constructedthe operating connection ll longer than necessary and join it to core 6by the relatively rigid connection it.

In operation the small rapid frequency vibrations of core 6 will beabsorbed in the resilient connection I? and contact beam 9 will remainsubstantially free from such vibrations. However, the relatively slowvibrations which are caused by the continual small voltage fluctuationson most load circuits will not be damped out by the resilient connectionll. Therefore, in order to prevent the practically continual operationof the regulator which is controlled by the contact making voltmeter,the contacts l6 and H are preferably so adjusted that it requires avoltage change of approximately two volts for the contact beam to gofrom one contact to the other. Inthis way the small voltagefluctuations, which usually are less than two volts, will merely cause afree motion, or vibration, of the contact beam between the contacts Hiand H, without touching them. This prevents undue wear and operation ofthe regulator and meter contacts without detracting appreciably from thespeed of operation of the arrangement upon voltage changes in excess ofthe usual small fluctuations.

I have found that with the above described arrangement relatively largeand sudden voltage changes on the regulated circuit cause such quickaction of the contact making voltmeter that a rebound of the contactstakes place thereby causing injurious arcing of the contacts. Itherefore provide a relatively loose type of damping means which I haveillustrated as an air dashpot I9. This dashpot has a relatively light,loosefitting piston 26, the rest of the dashpot being filled with air orany other suitable low density fluid. This arrangement .acts to damp orretard relatively large, sudden movements of the contact making meter,but it has no appreciable effect on slow movements of the meter or onrelatively rapid small movements of the meter. I find that thisarrangement effectually prevents rebounding of the contacts.

The resilient connection I! produces a further advantageous result inthat it causes a snap action of the contacts whereby the circuits arerapidly made and broken. This of course reduces arcing at the contactsand prolongs their 5 life. The operation of the system as a whole shouldnow be clear to those skilled in the art. Thus, if the voltage ofregulated circuit I decreases the energization of magnet 4 is weakenedand the raise contacts I 0 of the contact-making voltmeter .close,thereby completing energizing circuits for motor 3 and holding coil l2.The circuit for motor 3 is such as to cause this motor to operateregulator 2 in a manner to insert a voltage boost in circuit I. Thisaction continues until a voltage of circuit I is slightly above thevoltage at which contacts H3 would normallytendto separate, when theincreased pull of coil 4 overcomes the pull of holding coil l2 and beam9 will be 20 returned to its mid position. Similarly, whenithe voltageof circuit l rises, lower contacts Hare closed thereby energizingholding coil l3 .and motor 3, in such a manner as to cause regulator 2to insert a voltage buck in circuit I. This will 25 continue until thevoltage falls slightly below the value at which contacts ll tend toopen, due to the pull of coil l3. When this pullis overcome the contactswill separate and the arm will return to its mid position.

In the modified arrangement shown in Fig. 2 the compensating spring -lis connected directly'to the stem of the core 6 instead of being ofi-setas in Fig. I. This allows core 5 to hang with its axis vertical, whichin some cases may result in an improved operation of the control magnet.Alsoa special bracket 2| is employed for connecting spring I1 to arm 9,and the other end of spring H is connected directly to the core stem.This is merely an alternative way of obtaining a relatively long springwhile keeping the meter structure compact.

While I have shown and described a particular embodiment of myinvention, it will be obvious to those skilled in the art that changesand modifications may be made without departing from my invention and I,therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secureby Letters Patent of the UnitedStates is:-.-

An alternating current contact making voltmeter comprising, incombination, a pivotally mounted contact arm which issubstantiallybalanced with respect to its mounting, an operating magnettherefor, a vertically movable core for said magnet, a. spring forsupporting a portion of the weight of said core, a flat spring forproviding (2- an operating connection between said. core and said armwhich will not transmit to said arm any frequency vibrations of saidcore, said spring being longer. than the distance between said core andsaid arm, connections between the ends of said spring and said core andarm respectively, one of said connections being a bracket whose lengthequals the difference between the length of said spring and the distancebetween said arm and core, and a loosely damped dashpot connected tosaid core. V

' FRANKLIN J. CHAMPHN. I

